This invention relates generally to improved slip-type pliers tools that are frequently referred to as "water pump pliers". More particularly, but not by way of limitation, this invention relates to an improved slip-type pliers tool that is retained, when in the closed position of the tool, with the engaging surfaces thereon in a generally parallel, spaced relationship and one in which the space between the engaging surfaces on the tool can be adjusted in relatively small increments.
U.S. Pat. No. 3,854,351 issued Dec. 17, 1974, to Ralph Martin, illustrated in its background discussion, a typical, generally available water pump pliers. In that type of pliers, the incremental spacing between the engaging surfaces of the pliers is controlled by the position of an arcuate lug located in a selected one of a series of concentric arcuate grooves formed in the opposite jaw member.
Another type of pliers that is available, is manufactured by a German company under the trademark "Olin". The Olin pliers has a slot formed in one of the jaw members in which a toothed, spring-loaded ratchet dog is disposed. One edge of the slot is formed with mating teeth, and pivotal movement of the pliers toward the open position moves the ratchet out of engagement with the teeth permitting sliding movement to incrementally adjust the space between the engaging surfaces of the pliers. Movement of the ratchet dog is controlled by a coil spring that encircles the pivot pin of the pliers.
Both of the foregoing types of pliers have been accepted commercially and both operate reasonably satisfactorily. However, pivotal movement of the jaw members toward the closed position results in a non-parallel relationship between the engaging surfaces. When utilizing the pliers to loosen nuts or bolts having engaging surfaces disposed in parallel planes, such pliers can cause damage to the corners of such fasteners which may result in such fasteners being unserviceable.
An object of this invention is to provide an improved, slip-type pliers tool that cannot be closed beyond the position wherein the engaging surfaces thereon are in generally parallel, spaced relationship.
Another object of the invention is to provide an improved slip-type pliers tool wherein the incremental spacing between the engaging surfaces can be varied in very small, pre-selected increments.